DE102021210039A1 - Method for producing a control device for a motor vehicle and control device - Google Patents

Abstract

The invention relates to the manufacture of a control unit (1) for a motor vehicle. An electronics housing (2) is provided for the control unit (1) and an integrated circuit (6) is positioned and fixed in the electronics housing (2). A circuit carrier (4) is then positioned in the electronics housing (2) and then the integrated circuit (6) is contacted with the circuit carrier (4) by means of a welding process.

Description

The invention relates to a method for producing a control unit for a motor vehicle. Furthermore, the invention relates to such a control device.

Control units are used in many places in motor vehicles. Basically wherever an element is moved, for example on a motorized window regulator, but also in other motorized units, for example also in air conditioning units, a traction motor, coolant pumps or the like. In some cases, such control devices for several elements are also combined to form a common unit. The control units often have at least one integrated circuit, which is usually set up and provided for processing a specific task. For example, such an integrated circuit can be a power module (for example an IGBT power module) that is used as an inverter. Optionally, however, the integrated circuit can also represent a user-specific circuit that serves as a type of processor for committed (here “hardwired”) operations.

Such integrated circuits are usually connected to a circuit carrier by means of what is known as through-hole mounting technology (“THT”). So-called wave soldering is regularly used, in which solder is applied from the rear of the circuit carrier. The assembly experience and the correct mechanical equipment usually lies with the electronics supplier. The disadvantage of this, however, is that during assembly of circuit carriers (printed circuit boards) already equipped, at least with the integrated circuit, in the specified electronics installation space, undesirable (mechanical) stresses can occur, which can lead to damage to the integrated circuit and/or the circuit carrier.

The object of the invention is to improve the assembly of a control device, in particular one for a motor vehicle.

This object is achieved according to the invention by a method having the features of claim 1. This object is also achieved according to the invention by a control unit having the features of claim 8. Advantageous and partly inventive embodiments and further developments of the invention are in the dependent claims and the following description set forth.

The method according to the invention is used to produce a control unit for a motor vehicle. According to the method, an electronics housing is first provided for the control unit. An integrated circuit (also referred to as “IC” for short below) is then positioned in this electronics housing and fixed, preferably mechanically. Furthermore, a circuit carrier is positioned in the electronics housing (particularly after the IC has been fixed). The integrated circuit is then contacted with the circuit carrier (preferably already fixed in the electronics housing) by means of a welding process.

This procedure advantageously eliminates the pre-assembly of the IC on the circuit carrier and avoids establishing a soldering process for electronic components (usually wave soldering in the case of THT-mounted electronic components) in what is usually a more mechanically oriented “manufacturing facility” for motor vehicle control units. Nevertheless a qualitatively sufficient and also mechanically stable electrical contact is realized by the welding for contacting the IC with the circuit carrier.

Welding systems and/or corresponding welding processes are included in the above Manufacturing facilities are usually available anyway or are easier to integrate, since no preheating of the contact points and/or the affected components is required when contacting by welding.

In a preferred variant of the method, the IC is welded to the electronics housing, in particular inside it. Such an IC is often housed in a plastic housing anyway, which can thus be connected in a simple but also stable manner to the electronics housing, which is optionally also made of (in particular thermoplastic) plastic. For example, vibration welding, ultrasonic welding or laser beam welding are used here.

In each of the alternative process variants, the IC is screwed, riveted, glued or the like to the electronics housing for fixing to or in the electronics housing.

In an expedient variant of the method, a contact element (e.g. a "contact foot" or "leg") of the IC is connected directly to a corresponding counterpart of the circuit carrier (in particular a conductor track or an end of such a conductor track designed as a "solder pad" on a printed circuit board, or a corresponding one Section of a stamped grid)) contacted.

In an expedient development of the above variant of the method, the contact element of the integrated circuit is bent into an intended contact position after the circuit carrier has been positioned in the electronics housing. In particular, in this case the corresponding contact element is deformed in such a way that this contact element is brought into contact with the counterpart (preferably also permanently without a welding process). As a result, tolerance compensation can advantageously take place when the circuit carrier is installed in the electronics housing.

In an alternative but equally expedient variant of the method, the contact element of the integrated circuit is indirectly contacted by means of an intermediate piece with the corresponding counterpart of the circuit carrier.

In this case, the intermediate piece is preferably used for spatial bridging between the counterpart and the contact element. In particular, after the circuit carrier has been positioned in the electronics housing, the intermediate piece is connected to the counterpart and the contact element, preferably using the welding process in each case. As a result, the “bending into position” of the contact element described above can be omitted.

In optional process variants, resistance welding or ultrasonic welding is used as the welding process. Within the scope of the invention, however, laser beam welding is equally conceivable and optionally also provided.

The control device according to the invention for a motor vehicle has the electronics housing described above and the integrated circuit (IC), which is positioned and fixed in the electronics housing. In addition, the control unit has the circuit board, which is positioned in the electronics housing. The IC is contacted with the circuit carrier by means of a welding process.

The control unit is therefore preferably the control unit produced by means of the method described above.

The control unit therefore has the features described above in the context of the method and the advantages resulting therefrom in a corresponding manner.

The IC is preferably welded to the electronics housing. Alternatively, the IC is screwed, glued or the like in the electronics housing.

The electronics housing preferably has joining surfaces that are prepared in a known manner for the corresponding joining technique (for example by providing screw holes, bare and smooth surfaces for welded joints, etc.).

Furthermore--as described above--the corresponding contact element (possibly several contact elements) of the IC is in direct contact with the corresponding counterpart of the circuit carrier by means of the intermediate piece.

In an alternative variant, the or the respective contact element is contacted directly with the corresponding counterpart.

In one variant, the circuit carrier is designed as a printed circuit board, in particular as a printed circuit board. In an alternative variant, the circuit carrier is a pressed screen.

The electronics housing is preferably designed in two parts with a housing trough and a housing cover. In an optional embodiment, the housing trough and/or the housing cover are made of a (preferably thermoplastic) plastic. Alternatively, the housing trough and/or housing cover are made from a metal, for example steel, an aluminum alloy or a zinc alloy, in particular as a (pressure) cast part, for example in order to be able to use a higher material-related heat resistance.

Here and in the following, the conjunction “and/or” is to be understood in particular in such a way that the features linked by means of this conjunction can be designed both together and as alternatives to one another.

• 1 in einer schematischen Teilschnittansicht ausschnitthaft ein Steuergerät für ein Kraftfahrzeug,
• 2 in einem Ablaufdiagramm schematisch ein Verfahren zur Herstellung des Steuergeräts,
• 3 in Ansicht gemäß 1 ein alternatives Ausführungsbeispiel des Steuergeräts.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Show in it:

• 1 in a schematic partial sectional view of a detail of a control unit for a motor vehicle,
• 2 in a flowchart, a method for manufacturing the control unit is shown schematically,
• 3 in view according to 1 an alternative embodiment of the controller.

Corresponding parts are always provided with the same reference symbols in all figures.

In 1 a control unit 1 for a motor vehicle is shown in a schematic partial sectional view. This has an electronics housing 2, which houses a number of electrical and electronic components. the elec Electronics housing 2 comprises a housing trough 2a, which is closed with a housing cover 2b in the illustrated correct assembly state. As such components, control unit 1 includes at least one circuit carrier in the form of a (especially printed) circuit board 4 and an integrated circuit (“IC 6” for short). In the present exemplary embodiment, the IC 6 forms an IGBT power module which is connected to the printed circuit board 4 in terms of signal transmission, specifically to corresponding conductor tracks 8 on the printed circuit board 4 .

In an alternative exemplary embodiment, the circuit carrier is formed by a pressed screen.

Based on 2 a method for producing the control unit 1 is described in more detail below. In a first method step S1, the electronics housing 2 is first provided, specifically first the housing trough 2a. In it (specifically on the bottom of the tub), the IC 6 is positioned and fixed in a second method step S2—separately from the printed circuit board 4. For fixing, the IC 6 is concretely welded to the housing trough 2a--which is made of thermoplastic material in the present exemplary embodiment. Subsequently, contact feet 10 of the IC 6, which serve as contact elements for contacting the circuit board 4, specifically correspondingly assigned conductor tracks 8 present there as a counterpart, are bent in the direction out of the housing trough 2a (if they are not bent in this direction anyway).

In a further method step S3, the printed circuit board 4 is inserted into the electronics housing 2—placed and fixed on supports that are not shown in detail. In addition, a respective free end of the bent-up contact feet 10 is bent down in the direction of the circuit board 4, so that this free end comes into contact with a corresponding conductor track 8 of the circuit board 4 (this point is also referred to as the contact pad of the conductor track 8).

In a fourth method step S4, the respective free end of the contact feet 10 is then welded to the corresponding conductor track 8. A weld point 12 is thus formed, which represents a mechanical and electrical connection between the printed circuit board 4 and the IC 6 . In a further method step S5, the housing cover 2b is placed on the housing shell 2a and fixed, and the electronics housing 2 is thus closed.

In 3 an alternative embodiment is shown. In order to avoid the step of bending the corresponding contact foot 10 onto the corresponding conductor track 8, an intermediate piece 14 is used here, which is welded both to the printed circuit board 4 and to the corresponding contact foot 10. Consequently, two welds 12 are formed here. The intermediate piece 14 forms an angle, one leg of which is connected to the printed circuit board 4 and the other leg to the contact foot 10 . As a result, a tolerance in the positioning of the printed circuit board 4 in the “height” between the housing trough 2a and the housing cover 2b can be compensated for in a particularly simple manner. For this purpose, the intermediate piece 14 is expediently first welded to the corresponding conductor track 8 . Then the contact foot 10 is welded to the other leg of the intermediate piece 14 .

The subject matter of the invention is not limited to the exemplary embodiments described above. Rather, further embodiments of the invention can be derived by the person skilled in the art from the above description. In particular, the individual features of the invention and their design variants described with reference to the various exemplary embodiments can also be combined with one another in other ways.

Reference List

1

control unit

2

electronics housing

2a

housing tray

2 B

housing cover

4

circuit board

6

IC

8th

trace

10

contact foot

12

weld

14

spacer

S1-S5

process step

Claims (10)

Method for producing a control unit (1) for a motor vehicle, according to the method - an electronics housing (2) for the control unit (1) is provided, - An integrated circuit (6) is positioned and fixed in the electronics housing (2), - A circuit carrier (4) is positioned in the electronics housing (2), and - then the integrated circuit (6) is contacted by means of a welding process with the circuit carrier (4). procedure after claim 1 , wherein the integrated circuit (6) is welded to the electronics housing (2). procedure after claim 1 or 2 , wherein a contact element (10) of the integrated circuit (6) is contacted directly with a corresponding counterpart (8) of the circuit carrier (4). procedure after claim 3 , wherein the contact element (10) of the integrated circuit (6) after the positioning of the circuit carrier (4) in the electronics housing (2) is bent into an intended contact position. procedure after claim 1 or 2 , wherein the contact element (10) of the integrated circuit (6) is contacted indirectly by means of an intermediate piece (14) with a corresponding counterpart (8) of the circuit carrier (4). procedure after claim 5 , wherein the intermediate piece (14) for spatial bridging between the counterpart (8) and the contact element (10) is used. Procedure according to one of Claims 1 until 6 , resistance welding, ultrasonic welding or laser beam welding being used as the welding process. Control device (1) for a motor vehicle, having - an electronics housing (2), - an integrated circuit (6) positioned and fixed in the electronics housing (2), and - a circuit carrier (4) which is positioned in the electronics housing (2), the integrated circuit (6) being contacted to the circuit carrier (4) by means of a welding process. Control unit (1) after claim 8 , wherein the integrated circuit (6) is welded to the electronics housing. Control unit (1) after claim 8 or 9 , wherein a contact element (10) of the integrated circuit (6) is contacted indirectly by means of an intermediate piece (14) with a corresponding counterpart (8) of the circuit carrier (4).

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